Managed Debugging Assistant 'PInvokeStackImbalance' has detected a problem in

问题显示：
Managed Debugging Assistant 'PInvokeStackImbalance' has detected a problem in 'D:\xx\xx\bin\Debug\xx.exe'.
Additional Information: A call to PInvoke function 'TestInterface!Demo.Cppmy.Control::InitLogWorkDir' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.

c#代码：
StringBuilder LogPath = new StringBuilder（xxxx）；
InitLogWorkDir(LogPath.ToString().ToCharArray());

接口：
[DllImport("xxxx.dll",xxxxxxx)]
[SecuritySafeCritical]
private static void InitLogWorkDir(char[] logDir);

C++代码：
void InitLogWorkDir(wchar_t* logDir)
{
wstring logDirWStr = logDir;
Log::SetPath(logDirWStr);
return;
} 

请问怎么修改
 谢谢

http://stackoverflow.com/questions/6089214/how-do-i-marshal-wchar-t-from-c-to-c-sharp-as-an-out-parameter-or-return-valu

http://topic.csdn.net/u/20110804/09/f35a170c-fee4-42be-83f4-abcc54ad6987.html